Motorola APX 7000 - Advanced Features; Sending SSA Notification to All Sites

Troubleshooting Charts: PA Failure 5-57
PA Failure – Page 9 (UHF2 PA)
Yes
No
9
Is current less
than 350 mA?
Use a spectrum
analyzer and high-
impedance RF probe.
Measure RF_IN_1 at
C1500.
Is the frequency
correct?
Is the power
level about 3
dBm?
Is the power
appoximately 37
dBm?
See FGU
troubleshooting
charts.
Check U1110 and
see FGU
troubleshooting
charts.
Measure power at
C1521.
Replace U1500.
Measure power at
C1707, and calculate
harmonic filter loss.
Is the loss less
than 1 dB?
Repair any issues
with 1700 series parts
in the harmonic filter.
PA and harmonic
filter are functioning
properly.
Measure TX current
at UHF2 test
frequencies.
If power issue is not
resolved.
4
No
No
No
Yes
Yes
Yes
Yes
Yes
No
Yes
Replace Q1501
Is current
approximately
500 mA?
Is current
greater than or
close to 2A?
No
Yes
Is voltage
approximate 6 V?
Measure DC voltage
at pin 4 of U1501
Measure voltage at
pin 5 of U1501
Is voltage
approximate 7 V?
Replace U1501
Measure voltage at
pin 3 of Q1101(UHF2/7800) or
pin 3 of Q1102 ( UHF2/VHF) or
pin 3 of Q1102(UHF1/UHF2)
Measure voltage at
pin 1 of Q1101 (UHF2/7800) or
pin 1 of Q1102 (UHF2/VHF) or
pin 1of Q1102 (UHF1/UHF2)
Measure DC voltage
at pin 5 of U1501
Is voltage
near 7.5 V
Is voltage
near 3 V
Trace voltages and check
for solderability issues on
R1102, Q1101, and Q1103.
Replace parts as necessary.
With the radio in RX
mode, measure the
DC voltage on
both pins of L1500
Is voltage
near 7.5 V
on both side?
Measure voltage at
pins 2 and 3 (UHF2/7800) or
pins 7 and 6 (UHF2/VHF) or
pins 7 & 6 (UHF1/UHF2) of
U1119. They should be
5 V and 2.775 V respectively.
Measure voltage at
pin 1 of Q1101(UHF2/7800) or
pin 1 of Q1102 (UHF2/VHF) or
pin 1 of Q1102(UHF1/UHF2)
With the radio in RX
mode, measure the
DC voltage on the
drain of Q1500.
With the radio in RX
mode, measure the
resistance on the
node shared by
C1512 and C1511.
Is voltage
near 7.5 V?
Check L1505 under
sheild SH10 for
solderability issues
and replace as necessary.
.
In TX mode, measure
the voltage on pin 4
of U1501.
Is the voltage
near 6 V?
Is the TX current
between 300
and 900 mA?
The PA is likely
damaged. Replace
Q1500.
Is the TX current
above 900 mA?
Lift shield SH10 and check
for solderability or part
issues on all 1500 series
parts. Replace parts as
necessary.
If no issues found, lift shield
SH13 and check for solderability
or part issues on all 1200 series
parts. Replace parts as
necessary.
4
Is TX current just
above standby
current?
If power issue is not
resolved.
The PA and Driver are likely
damaged. Replace Q1500
and U1500.
Check resistors R1503, R1504,
R1502, R1500,R1506 and
R1505 for resistance and
solderability issues and replace
as necessary.
If resistance is very low, in the
100's of ohms,and there are
no issues with the resistors
then there is a gate short on the PA.
Clear short or replace Q1500.
Is the voltage
below 4 V?
10
10
If the voltage is between 4 and 5.5 V then
the control loop should be working and
power should be available. Check the
coaxial cables and surface mounted coaxial
connectors.
Were the
connections
OK?
3
Replace cables, or
connectors J101 or
J102.
No
No
No
No
No
No
Yes
Yes
Yes
Is there
7.5 V on C1102?
Check L1500 for
solderability issues and
replace as necessary.
Check E1101 for
solderability issues
and replace as necessary
Yes
Yes
Yes
No
Is the resistance
near 9.9K Ohms?
Yes
No
Yes
Yes
Yes
Yes
Yes
No
No
No
No
Yes
No
Yes
Is voltage
approximate 0 V?
Replace
Q1103 (UHF2/7800) or
Q1104 ( UHF2/VHF) or
Q1104 (UHF1/UHF2)
No
No
Is voltage
greater than 1.5 V?
Measure voltage at
pins 2 and 3 (UHF2/7800) or
pins 7 and 6 ( UHF2/VHF) or
pins 7 and 6 (UHF1/UHF2)
of U1119.
No
close to 5V & 2.775V
respectively?
pins 2 and 3 or
pins 7and 6
Are
Yes
Replace
U1119
Yes
Replace
Q1101(UHF2/7800) or
Q1102 (UHF2/VHF) or
Q1102(UHF1/UHF2)
Yes